Southern California Highway
Renumberings

As described on the Route Numbering pages,
California originally had two systems of numbering highways. The first system
was the legislative route number (LRN) system, which was used by the
legislature and the state highway department to refer to highways. The second
system was the signed route system, which consisted of state (white
spade-shaped shields) and US highways. Figure 2 shows how the old system looked
in Southern California.

(Click on image for a full-size
map. Full-size image size: 284K)

Figure 2. Los Angeles and
Vicinity(Map excerpted from the 1959 Rand McNalley
Road Atlas and Radio Guide, currently out of print. The map is found on
pages 58-59.)

It is interesting to compare the old system to the new system. Note the
lack of the now-familiar Interstate shields. In 1959, I-405 was State Route 7;
I-5 was US 99 or US 101; I-10 was US 60/70/99, I-701 was State Route 15, and
I-110 was State Route 11. Other non-freeway routes also had different numbers:
present-day Route 91 was Route 14 and Route 18; present-day Route 14 was Route 7. Some numbers, however, are the same to today: Route 27, Route 39, Route

The system got even more confusing when the legislative numbers were
brought into the picture. Figure 3 shows the Los Angeles and Vicinity inset map
from the 1963 state highway map. The numbers in squares represent the
legislative route numbers; the numbers in shields represent the signed route
numbers. Note how a single signed route number might have many legislative
route numbers. This made references to routes confusing.

On September 20, 1963, Senate Bill 64 became effective. This possible
called for a renumbering of the state highways. The state shields were changed
from black letters on a white background to white letters on a green
background. Why the color choice? California Highways and Public Works
says:

The colors were decided upon after a panel of engineers had
checked various color combinations in over-the-road tests. Blue and gold were
strong contenders but lost out when it was discovered that gold had the
tendancy to appear muddy at night while the white and green retained their true
hues.

Figure 5 shows the effects of this renumbering in Caltrans District 7.
It shows both the old and new legislative route numbers, and uses color to show
route continuity.

(Click on image for full-size map.
Full-size image size: 176K.)

Figure 5. 1963 District VII State
Highway Numbering Map

The 1963 maps are interesting for some of the highways that they show
that no longer exist. Many of these highways were short routes created until
the freeway system was established, and represented older routings. The
following are some examples of these:

Route 163. Part of LRN 4, this is the old US 99 routing before
I-5 was constructed.

Route 214. Part of LRN 178, this is the old surface street
routing of US 91.

Route 212. Part of LRN 77, this is the old surface street
routing of US 70.

A few years after the renumbering, a lot of the temporary bypass routes
were deleted (Route 42 was deleted at this time, but continues for some reason
to be signed by the state and show up on maps). By 1986, the system was much
closer to what we know today. Figure 6 shows the 1986 system. Routes shown with
routes in open circles were never adopted. The lines with open dashes are
currently under construction or construction is planned.